It is proposed to continue the study of cognitive development and organization by means of the cross-lagged panel correlation technique. A current finding concerning the importance of aural comprehension in cognitive development between grades 5 and 11 will be extended into the primary grades. Certain as yet unspecified experimental studies involving attentive processes, aural comprehension, and reading comprehension will also furnish pertinent information on the same population of students. Factor models appropriate for longitudinal developmental data will also be applied in order to further understanding of the role of aural comprehension in cognitive development and to integrate various approaches to cognitive development.